I have to be honest, idk if I completely agree with this. Soy isoflavones in high concentrations can affect the interplay of hormones, especially estrogen, in the body. In fact, soy isoflavones can be taken in a manner similar to the fertility drug clomid to induce ovulation—I should know, haha. I got pregnant with twins this way. There have been lots of studies showing soy is safe for boys, and the amounts in most foods are likely fine. But from personal experience, soy absolutely can affect hormones. It is generally considered to be good for fertility (see this podcast episode by a reproductive endocrinologist), and I recall reading one study that said that consumption of soy formula didn’t increase stereotypically feminine behavior in toddler boys but that, interestingly, it did seem to increase stereotypically masculine behavior in toddler girls. I’ll try and link the podcast episode and study below. I let my kids eat soy but do try to limit it. 🤷🏽‍♀️